Reciprocating mechanism



Dec 8,

E, GAUTHIER RECIPROCATING MECHANISM Filed Dc-2. 7. 1921 fWez 0r Ernes Gazhler Patented Dec. 8, 1925.

UNITED `STATES vPATENT OFFICE. i

ERNEST GAUTHIER, OF` CHICAGO, ILLINOIS, SSIGNOR TO WESTERN ELECTRIC COM- PANY, INCORPORATED, F NEW YORK, N. Y., A CORPORATION OF NEW YORK.

To ZZ whom 'it may concern.'

Be it known that I, ERNEST GAUTHIER, a citizen of the United States, residing at Chi cago, in the county of Cook and State oi Illinois, have invented certain new and useful Improvements in Reciprocating Mechanisms, of which the following is a full, clear`l concise, and exact' description.

This invention relates to improvements in the construction and operation of reciproeating mechanisms such as punch presses and has for its object to improve the construction and operation of such mechanisms to prevent breakage and injury to the parts thereof or the tools used therewith due to Overloads or careless operation.

y 'The improvements of this invention reside in general in the construction of the pitman or reciprocating part of the machine where-V by there is provided in this partof the mechanism an overload safety construction which will prevent damage to the parts upon excessive thrust upon the pitman. More specifically, the invention consists in the construction of the pitman or reciprocating part in two relatively movable parts normally retained against relative movement by means of shearable rings or devices which will be destroyed in response to excessive thrust to permit the relative movement of the two parts of the pitman and'prevent injury of the parts other than the shearing of the shearing rings. The thrust required to shear the rings is in excess of the force required to do any particular work for which the press designed but less than the force required to break or injure the parts of the press or the tools used therewith; The construction of the pitman is such that the rings may be quickly and easily replaced.`

VIn the drawings:

Fig. 1 is a fragmentary front view of a punch press equipped with the invention;

Fig. 2 is an enlarged fragmentary vertical sectional view taken on-'the line 2--21of Fig. 1; 'v

Y Fig. 23 is a plan section taken on the line 23e-'3 of Fig 2;

Fig. 4 is 'a plan section taken on the line 4-4 of Fig. 2; j

` Fig'f is an enlarged fragmentary view of j j i REQIPROCATING MEoHANIsM.

Application filed December '7, 1921. Serial No. 520,502.

Fig. 2 showing more clearly the device inserted between two members of the pitman;

F ig. G is a similar view showing the safety device sheared due to an overload on the press, and

Fig. 7 is a perspective view of the preferred form of the Vsafety device.

As shown in the drawings, the invention has been embodied in a power punch press of a well-known type, and referring to Fig. 1, a crank-shaft is indicated at 10 connected to a die head 11 by a pitman 12. The bed of the press is indicated at 13 between which and the die head 11 the work to be operated upon is positioned. The pitman 12, as shown in Fig. 2, is formed with a circular opening 14 at its lower end and is equipped with a. removable cap 15 which when removed forms an opening in the front face of the pitman 12 from its lower end to substantially the top of the opening 14. The cap 15 is secured to the pitman 12 by bolts 16. Closely fitting within the opening 14 'and at its lower end is a sleeve 17 made of two similar parts (see Fig. 3). At thelower end of the pitman and passino' between the two parts forming the sleeve 17 and into the opening 14 is a connection screw 18 for connecting the pitman 12 with the die head 11 through a ball type connection indicated at 20. Formed inthe two parts forming the sleeve 17 and that portion of the connection screw 18 inserted within the opening 14 is a butti-ess or ratchet type screw thread 21 which with the clamping in place of the two part sleeve 17, due to the bolting in place of the cap 15, forms a very effective means for securing the connection screw 18 in place after` the machine has been set for the work to be done. A suitable collar 22 is formed on the screw 18A for turning it when setting the machine.` Formed in the wall of the opening 14 and also in the Outer surface of the two- `part "sleeve 17 are coinciding annular grooves lor channels 23, 23. VIn the drawings the grooves are shown circular in cross section andcarried thereinis a suitable .length of wire forming a split ring 25,"as clearly shown in Fig. 7. The, grooves are of a size which will just admit a standard size of wire .--for instance, one-eighth inch in diameter.

It will readily be understood that the linear length of wire carried in the grooves 23 will vary according to the capacity of the machine and the delicacy of the tools used therewith. -In the drawings the ringsare shown full length-that is, alength sufficient to pass substantially around the two-part sleeveV 17. In another case the wire might extend only half way around the sleeve 17. In case a very delicate set of tools were being used, the length of wire, carried 1n a groove would be a fraction of a full length ring.

In machines not'equipped with an overload safety device, some part of the machine will break orbe overstrained when the capacity of thermachine is exceeded. This breaking o-r overstraining happens when the head 11 in moving down to the work meets with a resistance which the machine is not built for.v By mounting the connecting screw 18 in the split sleeve 17 and securing the sleeve to the pitman by the split rings 25 located in the grooves or channels 23 a cheap and easilyreplaceable member is provided in the pitman which will be sheared (see Fig. 6) when the capacity of the machine is exceeded, and thereby preventv injury to the pitman and other parts of the machine. The split rings after being sheared are easily removed` by merely removing the cap 15 and then moving the connection screw1S forward about its ball connection 20. The movement forward of the screw 18 and the size of thepopening 14 formed in the pitman 12 Vby removing the cap 15 is sufficient. to allow the two-part sleevel 17, held together by the sheared split ring 25 about the screw f17, to be unscrewed therefrom. The new split rings to be re'- placed may be coils cut from a long coil of wire prepared beforehand for replacement purposes, or the split rings may be cut to a suitable lengthvfroma straight piece of wire and formed around thesplit sleeve.

After placing the split rings in the grooves in the split sleeve the sleeve is screwedyback into place on the connection screw 18 and the screw moved back into the opening 14, after which the cap 15 is bolted lightly in place. The stroke vofthe, machine is then reset, if it is found necessary, by turning the collar 22 andthereafterthe cap 15 is nally bolted in place, which causes the threads on the two-part sleeve to be firmly wedged into the threads on the connection screw 18.

In the preferred embodiment-of the inventionthe split rings are of metal, preferably.

brass,andcircular yin cross section, but it will readily be understood that any suitable p material and/cross sectionalv shape may be used withsubstanti'ally the same results.

InV adapting the invention to. a machine theeapacity of the machine 'and the factor of safety at which it is to be operated is first de? cided. From this decision the number of split rings either full or partial and the cross sectional area thereof to be used in the pitman of the machine and which will be sheared before injury tothe pitman or other parts of the machine is calculated.

A punch press is designed with a large factor of safety to guard againstextremes of from no lload to great overloads, but in a punch press equipped with this invention, where provision is made to take care of all the excess loads, the factor of safety need not be as large, and therefore the rating can be greatly increased without the slightest danger of overstrains.

IVhat is claimed is:

1. In a punch press or similar operating mechanism, a pair of telescopic members forming the pitman of the mechanism, and a shearable element interposed between the adjacent surfaces of the telescopic members adapted to' normally retain them against relative movement but shearable by excessive thrust to permit relative movement of the two members.

2. In a punch press or similar operating mechanism, a pair of telescopic members forming the pitman of the mechanism, a shearable element interposed between the adjacent surfaces of the telescopic members adapted to normally retain them against relative movement but shearable against excessive thrust to permit relative movement of the two members, the outer of said telescopic members having a` removable portion to afford access to said shearable element.

3. In a punch press or similar operating mechanism, a pair of telescopic members forming a pitman vthe engaging surfaces of said members being provided with registering grooves7 and means in said grooves forming an operative connection between said members, said means being adapted to give in response to excessive pressure on the pitman to permit relative movement of the telescopic parts.

4. In a punch press or similar operating mechanism, a pair of telescopic members forming a pitman, the engaging surfaces ofsaid members being provided with coinciding annular grooves, and shearable rings inserted in said grooves to normally retain said members against relative movement.

5. In a punch press or similar operating mechanism, a pair of telescopic members forming a pitman, the engaging surfaces of said members being provided with coincid mg annular grooves, and metal rings of circular cross section located in said grooves adapted to retain said members against rel ative movement under normal thrust upon the pitman `but to be sheared by excessive thrust thereon to permit relative movement of the two members.

6. In a punch press or similar operating mechanism, a pitmzm comprising a screw threaded member, a screw threaded bushing adapted to receive seid member, a two-part socket member adapted to receive the bushing, and removable means cooperating With seid bushingand said socket member to normally hold them against relative movement butresponsive to excessive thrust on the pitman to permit relative movement of said bushing and socket.

In Witness whereof, I hereunto subscribe my name this 25 day of November A. D,

ERNEST GAUTHIER. 

